Return-Path: Received: (qmail 32612 invoked from network); 13 Dec 2002 10:54:24 -0000 Received: from netmail01.services.quay.plus.net (212.159.14.219) by mailstore with SMTP; 13 Dec 2002 10:54:24 -0000 Received: (qmail 1151 invoked by uid 10001); 13 Dec 2002 10:55:17 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from post.thorcom.com (193.82.116.70) by netmail01.services.quay.plus.net with SMTP; 13 Dec 2002 10:55:16 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.10) id 18MnT0-0006Uo-00 for rsgb_lf_group-outgoing@blacksheep.org; Fri, 13 Dec 2002 10:54:50 +0000 Received: from [134.58.10.57] (helo=mail3.cc.kuleuven.ac.be) by post.thorcom.com with esmtp (Exim 4.10) id 18MnSz-0006UD-00 for rsgb_lf_group@blacksheep.org; Fri, 13 Dec 2002 10:54:49 +0000 Received: from dell-rik.fys.kuleuven.ac.be (pc-10-33-165-177.fys.kuleuven.ac.be [10.33.165.177]) by mail3.cc.kuleuven.ac.be (8.12.1/8.12.1) with ESMTP id gBDAsJSA079316 for ; Fri, 13 Dec 2002 11:54:19 +0100 Message-ID: <5.1.0.14.0.20021213095059.02bde040@pb623250.kuleuven.be> X-Sender: pb623250@pb623250.kuleuven.be X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Fri, 13 Dec 2002 12:01:07 +0100 To: rsgb_lf_group@blacksheep.org From: "Rik Strobbe" In-reply-to: References: <002301c2a1fb$c711f020$0504210a@c.scope> MIME-Version: 1.0 Subject: RE: LF: Antenna tests Content-Type: text/html; charset=windows-1252 X-Spam-Status: No, hits=-0.6 required=5.0tests=IN_REP_TO,MAILTO_LINK,REFERENCES,SPAM_PHRASE_01_02version=2.42 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Content-transfer-encoding: 8bit Hi Hugh and Gary,

If you have a 136kHz TX it's rather easy : measure the antenna current and the TX output voltage, R = U/I. The calculated R is the total loss resistance + radiation resistance, but the last is far less than 1 Ohm so you can ignore it. If you want to know the ground loss (or better said environmental losses) you have to subtract the loss in the loading coil.
An more direct resistance measurement can be done using a Wheatstone bridge or something similar
("antenna analyzer"), have a look here for some construction ideas :
http://home4.swipnet.se/~w-41522/bridge/bridge.html
http://www.lwca.org/library/articles/k0lr/lfanalyz/lfanalyz.htm
http://www.lwca.org/library/articles/k0lr/lfanalyz/mfj259.htm
http://www.geocities.com/df8zr/zx.html
Some interesting reading on ground loss at G3NYK's webpage : http://www.alan.melia.btinternet.co.uk/aelossbr.htm

73, Rik ON7YD

At 21:43 12/12/2002 +0000, you wrote:

Hi Hugh,

Not a dumb question if you don't know the answer.

I would also like to know how to measure the earth resistance or series loss resistance of my antenna when it is finally completed and also what it tells us about the system.

73

Gary G4WGT

-----Original Message-----
From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of g6tmk
Sent: 12 December 2002 16:29
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Antenna tests

Hi Dick and group,
Please forgive the dumb question ...

Dick wrote:
I measured the earth resistance at my station several times this year:

On the dry day of 6 April it was 21 ohm...

How did you measure the resistance ?

73
Hugh M0WYE